Power mechanism for noiseless typewriter



March 28, 1961 E. a. ISRAELSON ETAL 2,976,977

POWER MECHANISM FOR NOISELESS TYPEWRITER Filed May 14, 1959 III, I/

INVENTORS: EVERT G. ASRAE JOHN C. Mama/ t A TTOR /gy POWER MECHANISM FOR NOISELESS. rrrawnrran Filed May 14, 1959, Ser. No. 813,159 V 14 Claims. (Cl. 197-17) This invention relates to power operated typewriters,

and particularly to a typewriter having a power mechanism actuated by a continuously driven power roll operated by an electric motor. 7

One object of the invention is to provide a power mechanism for operating the type actions of typewriters in operation because of the use of a reduced number of moving parts; and has an accelerated motion to produce 1 a more rapid action in keeping with typing done at high speed.

The use of the present invention is illustrated herein;

as applied to a machine in which the keyboard includes 5 a parallel action shown in an application of common assignee Serial No. 810,736 filed May 4, 1959 and to use in a noiseless typewriter as shown in Patent No.;2,862,- I 591, granted to E. G. Israelson on December 2, 1958.

Other objects and structural details of the invention will be apparent from the following description when read in connection with the accompanying drawing, in which: I u Q Figure '1 is a view in sectional elevation of the power mechanism of the invention shown in non-operating posi-j: tion, and Figure 2 is'a fragmentary plan view of one end ofthe mechanism -shown in Figure 1 and illustrating diagram matically the relative positions of the main and sub frame mounting. 1 i Referringto the drawings in' detail, 10 indicates generally'one unit of the powermechanism of a. typewriter? which latter includes a power driven roll 11, journalled; in suitable sides 12 of an inner frame that is removable as a unit from a main frame 13 of the-machine, and;

is biasedpby a spring 34, in counterclockwise direction v is extended as at 50 to overlie a ribbon universal bail bar '51 shown in. outline and disclosed in another copendingapplication of commonv assignee, Serial No. 808,806

which roll 11 is common to each unit 10 of the power. mechanism. Eachbfthe units includes an eccentrically-g mounted power'arm cam 14 for operating engagementv with the power roll 11 to cyclically oscillate a type'bar-r power arm '16. The cam 14 is pivoted as at 17 to thee-: arm 16 which, in turn, is'pivoted on a rod 18in the upperend of a cross bar 19which extendsgbetween the side frames12 and which is slotted to locate thearmy. '16 and its associated parts. Y

' When one of therkeys 21 of the keyboard is depressed,

against a stop bar 36, the spring being secured at one end 1 to a bracket 37 to the latter of which is also fastened a spring 38 for urging the power arm 16 in counterclockwise direction so that cam 14 will engage the power roll 11 when the trigger 28 is lifted by the rocking movement of the bell crank 23 and the upper fiat end 41 of the latch 33 rides 01f a seat portion 39 on the underside of said power arm 16.

The cam 14, which may have a knurled surface, is normally spaced slightly from the power roll 11, and is provided with an annular groove 42 which gradually deepens to provide a latch recess 43 at one end of said groove. When the latch 33 is swung clockwise by the trigger 28 the upper end 41 of the latch will move out from beneath the seat portion 39 'on the underside of the power arm 16 and the spring 38 will then swing the arm 16 counterclockwise on its pivot 18 to engage the cam 14 with the power roll 11.

When the cam 14 rotates clockwise in contact with power roll 11, which rotates counterclockwise, the latch 33, which has been released by the trigger 28, is further swung by the eccentric movement of the cam 14 and the tab 46 on the toe end 44 of the latch engages the trigger 28 and holds it in an inoperative position until the toe 5 end 44 of the latch rides into the stop recess 43 to let the shouldered upper end 31 of the trigger 23 engage the r .nose 32 of the latch 33, and'to let the upper'end 41-of the latch 33 be pulled by spring 34 to come to-restbeneath the seat 39 on the power arm 16 as limited by the stop 7 bar 36;. The groove 42 which gradually deepens provides an accelerated counterclockwise swing for the toe end of ithe latch 33 which is faster than the swing of the cam 14 and arm 16 in rightward direction so that time is provided for the upper end 41 of the latch to snap under the seat 39 of-the power arm 16 as the same is lowering under the pull of the spring 38 as permitted by the eccenytric rotation of the cam 14. The rotation of the latter is t'No. 2,638,199, granted to F. W. Schremp, May 12, 1953,

for actuating the usual form of type bars or, as in the present instance, may be used to actuate the type bar action of aanoiseless typewriter'of the kind shown in the patent above referred to and in which the operating operates the type bar action. I Each lever carries an adjusting screw 48 for engagement by the lift 611C149 of each power arm 16. The opposite end of each power arm filed April 24, 1959.

It is evident therefore that the power mechanism dis- TTlever 47 corresponds to a lever 47 shown herein which closed embodies a minimum number of-moving parts 1 including an accelerated action feature and a mechanismthat lends itself to ready incorporation as a removabl unit into a typewriter. I i

While we have shown and described what we consider to be a, highly desirable embodiment of our invention, it p is obvious that changes in form could be made without departing from. the spirit of the invention, and we there;

fore do not limit ourselves to the exact formherein shown aand described nor to anything less than the whole ofour,-

invention as hereinbefore set forth and a as hereinafter claimed. 1 H r What we claim as new and desire to secure by Letters Patent is:

power mechanism associated with said key levers and the power roll and including-eccentric cam means, power arm means supporting said cam means and connected to the type bars, and biased for movement to engage the cam means with the power roll for oscillating said power arm means to operate the type bars, latch means engaging said power arm means for holding said power arm means in position with the cam means outof engagement with said power roll, key lever controlled trip means for operating said latch means to release said power arm means for contact of the cam means with said power roll and means in said cam means for accelerating the movement of said latch means to power arm holding position.

2. In a power driven typewriter the combination with key lever means, type bar means and a power driven roll; of a power mechanism for operating said type bar means in printing action including an oscillatable power arm connected to the type bar means, an eccentric cam on the power arm for engaging the roll to oscillate said power arm, latch means coacting with said power arm to maintain the cam out of engagement withthe roll, trigger means controlled by. said key lever means for operating the latch means and freeing said power arm for engagement of said cam with the power roll and means in said cam for restoring said latch means to coact-ing relation with said power arm.

3. The combination with a typewriter having a main frame, a power operated roll and type bars in said main frame, a sub frame removable from the main frame and key levers in said sub frame; of a power mechanism contained in said sub frame and removably associated with said key levers and the power roll, said power mechanism including oscillatable power arm means connected to said type bars for operating said type bars, cam means mounted eccentrically in said power arm means, means for moving the power arm means to engage the cam means with said power roll to oscillate said arm means, latch means for blocking the action of said power arm moving means, trip means controlled by the action of said key levers for moving said latch means to unblocking position and thereby unblocking said power arm moving means for action and means in the cam means for restoring the latch means to blocking positon.

4. The combination with a typewriter having key lever means, type bar means and a power driven roll; of a power mechanism coacting with said key lever means and the roll for actuating said type bar means in printing action, said power mechanism including cam means, power arm means for supporting said cam means and movable to swing the cam means into andout of contact with the power roll to oscillate said power arm means, latch means for blocking movement of the power arm means to engage the cam means'withsaidroll, trip means for initially moving said latch means. to' unblocking position and means in said cam means for accelerating the blocking movement of said latch means. i

'5. A typewriter as set forth in claim 4, in which said accelerating means includes a circumferential groove in the cam means terminating in a recess of varying depth and constituting a seat for an end of said latch means and a stop for the cam means. s V

6. Ina typewriter, key levers, type bars, a power operat'ed roll for operating said typerbars under control of said key levers, a power mechanism associated withisaid key levers and the power roll and including eccentric cam means, power arm means biased for movement to engage the cam means with the power roll for'cyclically oscillating the power arm means and operating said type bars, latch means blocking operation of the .power arm means in said biased movemenn'key lever controlled trip means for moving the latch means to, unblocking posifor restoring said latch means to blocking position at the end of each cyclical oscillation of said power arm means.

7. A typewriter of the character set forth in claim 6 including a support to which said power arm means and latch means are pivoted, a nose portion on said latch means engaged by said trip means for swinging the latch means to non-blocking position and a toe on the latch means for moving said trip means out of operating engagement with said latch means.

8. A typewriter of the character set forth in claim 6 including a seat portion on said power arm means with which one end of said latch means coacts to retain said power arm means in blocked position, and stop means on the latch means for holding the cam means from rotating when the latch means is in blocking position.

9. In a typewriter, the combination with key levers, typebars, and a power operated roll for operating said type bars under control of said key levers; of a power mechanism intermediate said key levers and the type bars and including pivoted power arm means biased for swinging movement toward said power roll, cam means carried by said power arm means for engaging the power roll to impart cyclically an oscillating movement to said power arm means, latch means biased to a holding engagement position between the cam means and said power arm means, trip means controlled by the key levers for moving the latch means outof holding engagement with the cam means and the power arm means for engagement of the cam means with the power roll, and means in said cam means for automatically restoring said latch means to said holding engagement position near the end of each cycle of oscillating movement of said power arm means.

10. A typewriter of the character set forth in claim 9 in which said latch restoring means includes stop means for arresting the movement of said cam means.

11. A typewriter of the character set forth in claim 9 in which said latch restoring means includes a groove in the cam means and a latch movement accelerating recess at one end of said groove.

12. A typewriter of the character set forth in claim 9 including stop bar means providing an abutment for engagement by said latch means at said holding engagement position.

13. A typewriter of the character set forth in claim 9 in which said trip means has a shoulder for engagement with the latch means to operate the latter and a tab on said latch means for engaging said trip means to detach the latter from operating engagement with said latch means.

14. In a typewriter, the combination with key lever means, type bar means, and a'power operated roll for operating the type bar means under control of said key lever means; of a power mechanism associated with the key lever means, the type bar means and the power roll, said mechanism including power arm means pivoted for oscillating biased movement between the type bar means "and the power roll, eccentric cam means carried by said References Cited in the file of this patent UNITED STATES PATENTS 2,326,312 Thompson Aug. 10, 1943 2,638,199 -Schremp May 12, 1953 p 'FOREIGNPATENTS 552,797 Great Britain Apr. 23, 1943 

